JPS63174039A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain a photosensitive compsn. improving the decoloration of an image area during printing with ultraviolet-curing ink by using a high molecular coloring material produced by bonding a dye to a high molecular compd. by ionic bond as a coloring substance. CONSTITUTION:This photosensitive compsn. contains photosensitive diazo resin, a lipophilic high molecular compd. and a coloring substance, and a high molecular coloring material produced by bonding a dye to a high molecular compd. by ionic bond is used as the coloring substance. The high molecular coloring material is a polymer having 1,000-500,000mol.wt. and contg. structural units each having an anionic or cationic group, e.g., a homopolymer of ethylenic unsatd. sulfonic acid or a salt thereof or a copolymer of the monomer with one or more kinds of other copolymerizable ethylenic unsatd. monomers. When the photosensitive compsn. is used, a photosensitive planographic printing plate improving decoloration during printing with ultraviolet-curing ink is obtd.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a negative photosensitive composition that can be used for producing printing plates such as photosensitive lithographic printing plates, letterpress plates, intaglio plates, and gravure plates. The present invention relates to a photosensitive composition used in a photosensitive lithographic printing plate. More specifically, the present invention relates to a photosensitive composition used in a photosensitive lithographic printing plate that improves color loss in image areas during development processing, plate cleaning with a plate cleaner or the like, printing with ultraviolet curable ink, and the like.

[Prior Art] Conventionally, a diazo resin and a binder resin, etc. are mixed to form a photosensitive composition, and this is applied to an aluminum plate that has been surface-treated by roughening, anodizing, etc. to form a photosensitive lithographic printing plate. are widely used. At this time, a dye is included in the developer or in the photosensitive composition in order to visualize the image during printing. For example, dyes such as acridine dyes, cyanine dyes, styryl dyes, and triphenylmethane dyes, and pigments such as phthalocyanine are used.

[Problems to be solved by the invention] However, with these conventionally used dyes, when development is carried out for a long time, it is difficult to develop the dyes by impregnating a cellulose sponge with the developer and repeatedly rubbing the plate. In cases where dyes are eluted from the image area (e.g. when printing is performed with ultraviolet (UV) curable ink, etc.) when cleaning is repeatedly performed using plate cleaners containing organic solvents or surfactants during printing, etc. Color loss) occurred, making it difficult to determine the presence or absence of a resist image, which was a practical problem.

On the other hand, a water-soluble polymer having a structural unit derived from ethylenically unsaturated sulfonic acid or its salt can be used as a coloring agent for wood, paper, m-fiber, or as a coloring agent for aqueous polymer emulsions, water-soluble polymers, and aqueous inks. A water-soluble polymer coloring material obtained by dyeing with a cationic dye was published in JP-A-60-1
It is disclosed in Japanese Patent No. 1542. The purpose of this is to provide an aqueous colorant that improves the storage stability of dyes and the light resistance of cationic dyes, and that enables coloring at higher concentrations than pigments.

The inventors of the present invention thought that it would be possible to improve the above-mentioned color loss in the image area during printing by polymerizing the dye, and as a result of extensive research.

We have arrived at the present invention.

[Means for Solving the Problems] That is, an object of the present invention is to solve the above-mentioned drawbacks and to provide a photosensitive composition for use in printing plates such as photosensitive lithographic printing plates that provide images with improved color loss. The above object of the present invention is to provide a photosensitive composition containing a photosensitive diazo resin, a lipophilic polymer compound, and a coloring substance, in which a dye is bonded to the polymer compound by ionic bonding as the coloring substance. This is achieved by using a polymeric coloring material that is

The present invention will be specifically explained below.

The photosensitive diazo resin used in the present invention includes:
For example, Photographic Science and Engineering (Photo, Sci, Eng.

) Volume 17, Page 33 (1973), U.S. Patent No. 2.0
No. 63,631, No. 2,679,498, No. 3,
A diazo compound and an active carbonyl compound, such as formaldehyde, acetaldehyde, or benzaldehyde, whose manufacturing methods are described in the specifications of No. 050,502 and JP-A-59-78340, etc., are mixed with sulfuric acid, phosphoric acid, hydrochloric acid, etc. Diazo resins obtained by condensation in an acidic medium, diazo resins obtained by condensing a diazo compound and a diphenyl ether derivative whose production method is described in Japanese Patent Publication No. 49-4001, etc. can be used. .

The counter anion of the diazo resin used in the present invention is
It contains an anion that forms a stable salt with the diazo resin and makes the resin soluble in organic solvents.

These include organic carboxylic acids such as decanoic acid and benzoic acid;
Contains organic phosphoric acids and sulfonic acids such as phenyl phosphoric acid,
Typical examples include methanesulfonic acid, chloroethanesulfonic acid, dodecanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, mesitylenesulfonic acid and anthraquinonesulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, hydroquinone Sulfonic acid, 4-acetylbenzenesulfonic acid, dimethyl-5
- Aliphatic and aromatic sulfonic acids such as sulfoisophthalate, 2.2', 4.4'-tetrahydroxybenzophenone, 1,2.3-trihydroxybenzophenone, 2.2', 4-trihydroxybenzophenone, etc. Hydroxyl group-containing aromatic compounds, halogenated Lewis acids such as hexafluorophosphoric acid and tetrafluoroboric acid, C 0. ,
Examples include perhalogen acids such as IO, but are not limited thereto. Among these, particularly preferred is hexafluorophosphoric acid.

The lipophilic polymer compounds used in the present invention include polyamide, polyether, polyester, polycarbonate, polystyrene, polyurethane, polyvinyl chloride and its copolymers, polyvinyl butyral resin, polyvinyl formal resin, shellac, epoxy resin,
Examples include phenol resin and acrylic resin.

Preferably, copolymers of the monomers shown in (1) to (12) below, usually having a molecular weight of 20,000 to 200,000, are used.

(1) For example, N-(4
-hydroxyphenyl)acrylamide or N-(4-
hydroxyphenyl) methacrylamide, 0-1m-1
p-Hydroxystyrene, 0-, m-1p-hydroxyphenyl-acrylate or -methacrylate.

(2) Seven polymers having an aliphatic hydroxyl group, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, or N-(4-hydroxyethylphenyl)methacrylamide; (3) acrylic acid, methacrylic acid, maleic anhydride (4) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, acrylic acid, etc.
(Substituted) alkyl acrylates such as 2-chloroethyl, 2-hydroxyethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate, (5) methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, 2
-Hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-
(Substituted) alkyl methacrylates such as dimethylaminoethyl methacrylate, (6) acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxy Acrylamides or methacrylamides such as ethyl acrylamide, N-phenylacrylamide, N-nitrophenyl acrylamide, N-ethyl-N-phenylacrylamide, (7) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl Vinyl ethers such as vinyl ether, octyl vinyl ether, and phenyl vinyl ether.

(8) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate; (9) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene; (10) Methyl vinyl ketone. , vinyl ketones such as ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone, (11) olefins such as ethylene, propylene, isobutylene, butadiene, isoprene, (12) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinyl Pyridine, acrylonitrile, methacrylatetrile, etc. Furthermore, monomers that can be copolymerized with the above-mentioned polymers may be copolymerized. Also included are copolymers obtained by copolymerizing the above monomers modified with glycidyl methacrylate, glycidyl acrylate, etc., but are not limited thereto.

More specifically, a copolymer having a hydroxyl group and a copolymer having an aromatic hydroxyl group containing the fluorine listed in (1) and (2) above are preferable.

Furthermore, polyvinyl butyral resin, polyurethane resin, polyamide resin, epoxy resin, novolak resin, natural resin, etc. may be added to the above copolymer as necessary.

The lipophilic polymer compound used in the present invention is usually 40 to 98% by weight in the solid content of the photosensitive composition.

Preferably it is contained in an amount of 60 to 95% by weight. In addition, the photosensitive diazo resin used in the present invention is usually 1 to 50% by weight,
Preferably it is contained in an amount of 3 to 30% by weight.

In the present invention, the polymer coloring material used as a coloring substance is one in which a dye is combined with a polymer compound through ionic bonding. The polymer compound has a molecular weight of 1,000 to s and contains a structural unit having an anionic group or a cationic group.
oo, ooo polymer, for example, a homopolymer of ethylenically unsaturated sulfonic acid or its salt, ethylenically unsaturated carboxylic acid or its salt, ethylenically unsaturated amine or ammonium salt, or can be copolymerized with these. Examples include copolymers with one or more other ethylenically unsaturated monomers. In the case of a polymer containing a structural unit having an anionic group, the polymer compound is dissolved at pH 2 to 8 in water or a mixture of water and an organic solvent.
A polymeric coloring material can be obtained by reacting with a cationic dye at a temperature of 0.degree. C. or higher. On the other hand, in the case of a polymer containing a structural unit having a cationic group, a polymer coloring material can be obtained by reacting it with an anionic dye.

Examples of ethylenically unsaturated sulfonic acids or salts thereof include styrene sulfonic acid, vinylbenzyl sulfonic acid,
Vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, acryloyloxyethylsulfonic acid, methacryloyloxypropylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid and salts thereof, such as lithium salt, sodium salt, potassium salt, Examples include ammonium salts.

Examples of ethylenically unsaturated carboxylic acids include 4-vinylbenzoic acid, 3-vinylphenylacetic acid, vinylacetic acid,
Acrylic acid, methacrylic acid, N-(4-carboxyphenyl)methacrylamide, and salts thereof, such as lithium salt, sodium salt, potassium salt, and ammonium salt, can be mentioned.

Examples of ethylenically unsaturated amines or ammonium salts include 2-aminoethyl acrylate and 2-aminoethyl acrylate.
-(Methylamino)ethyl, 3-(dimethylamino)propyl methacrylate or its hydrochloride, hydrochloric acid N, N, N-
Examples include trimethylmethacryloyloxypropylammonium.

Other copolymerizable ethylenically unsaturated monomers include, for example, alkyl acrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate; methacrylates such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate; Alkyl acids, vinyl esters such as vinyl acetate, vinyl benzoate, vinyl salicylate, styrenes such as styrene, methylstyrene, chlorostyrene, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxy methacrylate N-(p-hydroxyphenyl) methacrylamide having an alcoholic hydroxyl group such as ethyl; N-(p-hydroxyphenyl)methacrylamide having a phenolic hydroxyl group such as p-hydroxyphenyl methacrylate;
etc. can be mentioned. When copolymerizing, the structural unit having an anionic group or a cationic group is 30 to 9
9 mol% is preferred.

Polymers containing structural units having anionic or cationic groups used for the purpose of the present invention can be produced by various methods. For example, these monomers may be mixed with a conventional radical polymerization initiator such as potassium persulfate, ammonium persulfate, 1-butyl hydroperoxide, azobisisobutyro- Along with nitrile, benzoyl peroxide, etc.
It is usually obtained by one polymerization reaction under stirring at a temperature of 40 to 100"C".The molecular weight can be determined by appropriately adjusting the concentration of monomers in the polymerization system, concentration of radical polymerization initiator, polymerization temperature, etc. The desired molecular weight can be obtained.

Note that the purpose of the present invention is not limited in any way by the method for producing such a polymer.

For the purposes of the present invention, the molecular weight of the polymer containing structural units with anionic or cationic groups to which the dye is bound is from 1000 to 5oooooo, preferably from 1000 to 1
00000. More preferably it is 2000-5oooo.

As the cationic dye or anionic dye used for the purpose of the present invention, commonly known azo dyes, anthraquinone dyes, triphenylmethane dyes, etc. may be used.

Specifically, for example, methylene blue FZ, catylone I
Examples include, but are not limited to, DT-RLH, Cachilon Red 68H, Victoria Pure Blue BOH, and Brilliant Basic Cyanine 6GH.

These cationic dyes or anionic dyes may be reacted in an amount of usually 1 to 50% by weight, preferably 5 to 30% by weight, with respect to a polymer containing a structural unit having an anionic group or a cationic group.

The obtained polymeric coloring material is usually contained in the solid content of the photosensitive composition in an amount of 1 to 30% by weight, preferably 3 to 20% by weight.

The photosensitive composition of the present invention may further contain a color-changing agent that changes color tone by reacting with free radicals or acids. The color change agent is used for the purpose of obtaining a visible image by exposure (exposed visible image).

As the color changing agent, any agent that changes color tone by reacting with free radicals or acids can be used. Here, "change in tone" includes both a change from colorless to a colored tone, and a change from colored to colorless or a different colored tone. Preferred color changing agents are those that change color tone by forming a salt with an acid.

For example, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue #603 [manufactured by Orient Chemical Industry Co., Ltd.], Patent Pure Blue [manufactured by Sumitomo Mikuni Chemical Co., Ltd.], Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Violet, Methyl Triphenylmethane represented by Green, Erythrosin B, Pesic Tsuksin, Malachite Green, Oil Red, m-Cresol Purple, Rhodamine B, Auramine, 4-p-diethylaminophenylimino naphthoquinone, cyano-p-diethylaminophenyl acetanilide, etc. type, diphenylmethane type, oxazine type, xanthine type,
Iminonaphthoquinone-based, azomethine-based, or anthraquinone-based dyes are examples of color-changing agents that change color from colored to colorless or to a different colored tone.

On the other hand, examples of color changing agents that change color from colorless to colored include leuco dyes and 1, such as triphenylamine, diphenylamine, 0-chloroaniline, 1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p'-bis -dimethylaminodiphenylamine,
1.2-Dianilinoethylene, p, p', p''-tris-dimethylaminotriphenylmethane, p, p'-bis-dimethylamino diphenylmethylimine, p.

p',p''-triamino-0-methyltriphenylmethane, p,p-bis-dimethylaminodiphenyl-4-anilinonaphthylmethane, p,p'.

The first compound represented by p”-triaminotriphenylmethane
and secondary arylamine dyes.

Particularly preferably triphenylmethane and diphenylmethane dyes are effectively used, more preferably triphenylmethane dyes, especially Victoria Pure Blue BOH.

The above-mentioned color changing agent is generally added in the sensitive composition from 0.5 to about 10
% by weight is preferred, more preferably about 1-5% by weight.

Various additives can be further added to the photosensitive composition of the present invention. That is, alkyl ethers for improving coating properties, such as ethyl cellulose and methyl cellulose, plasticizers for imparting flexibility and abrasion resistance to the coating film, such as butylphthalyl, polyethylene glycol, tributyl citrate, and diethyl phthalate. , dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, etc. Polymers are also used as stabilizers to improve storage stability. Acrylic acid, tartaric acid, phosphoric acid, phosphorous acid, acrylic acid, oxalic acid, benzenesulfonic acid, 4-methoxy-2-hydroxybenzene-5-sulfonic acid, naphthalenesulfonic acid, etc. can be added. Particularly preferred for improving storage stability is polyacrylic acid.

These various additives vary depending on the intended use of the photosensitive composition, but are generally preferably added in an amount of 0.5 to 30% by weight based on the total solid content.

To form a layer of the photosensitive composition of the present invention on a support, predetermined amounts of the diazo resin, lipophilic polymer compound, polymeric coloring material, and, if necessary, additives are added to a suitable solvent (methyl cellosolve,
A coating solution of the photosensitive composition is prepared by dissolving it in ethyl cellosolve, methyl cellosolve acetate, acetone, methyl ethyl ketone, methanol, dimethyl formamide, dimethyl sulfoxide, water, or a mixture thereof, and this is coated on a support and dried. do it. The concentration of the photosensitive composition at the time of coating is preferably in the range of 1 to 50% by weight. When the photosensitive composition of the present invention is used in a photosensitive lithographic printing plate, the coating amount is the weight after drying. Generally 0.
It may be about 2 to 1 Og/m''.

Examples of the support to which the photosensitive composition of the present invention is applied include paper,
Various materials such as a plastic film, an aluminum plate, an aluminum foil, a zinc plate, a steel plate, a bimetallic plate, or a composite material thereof are used. When used in a photosensitive lithographic printing plate, an aluminum plate or a composite material of aluminum foil and other materials is preferable, and from the viewpoint of printing durability, an aluminum plate is particularly preferable.

From the viewpoint of adhesion or preservability of the photosensitive composition, the support, particularly an aluminum plate, or a composite material of aluminum foil and other materials, is used after being surface-treated by a known method.

For example, a method in which the surface of an aluminum plate is grained and then treated with a silicate (US Pat. No. 2,714°066), a method in which the surface is treated with an organic acid salt (US Pat. No. 2,714,
066), treatment with phosphonic acids and their derivatives (U.S. Pat. No. 3.220.8:12), treatment with potassium hexafluorozirconate (U.S. Pat. No. 2,946.68:1) ), a method of anodizing, and a method of treating with an aqueous solution of an alkali metal silicate after anodizing (US Pat. No. 3,181,461). The method of graining the surface of an aluminum plate is to degrease the surface and then use a brush polishing method, a ball polishing method, a chemical polishing method, or an electrolytic etching method, preferably to obtain a deep and uniform grain. The anodic oxidation treatment, which is carried out by electrolytic etching, uses an inorganic salt such as phosphoric acid, chromic acid, boric acid, or sulfuric acid, or an organic acid such as oxalic acid alone, or a mixture of two or more of these acids. This is carried out in an aqueous solution, preferably an aqueous sulfuric acid solution, by passing an electric current through an aluminum plate as an anode. The amount of anodic oxide film is 5 to 6
It is preferably 0 mg/dm2, more preferably 5 to 30 mg/dm2.

It is particularly preferable that the surface of the aluminum plate or aluminum foil is grained, then anodized, and then further treated with a silicate. ~3%, 1 at temperature 80-95℃
The treatment is carried out by immersion for 0 seconds to 2 minutes, and then preferably immersed in water at 40 to 95° C. for 10 seconds to 2 minutes.

Conventional methods are applied to the photosensitive material coated on the support. That is, by exposing a transparent original image having a line image, a halftone image, etc. to light, and then developing it with a suitable developer, a negative relief image can be obtained with respect to the original image.

[Example] Hereinafter, the present invention will be specifically explained by showing synthesis examples and examples of the diazo resin, lipophilic polymer compound, and polymer coloring material used in the present invention.

(Synthesis of Diazo Resin-1) 14.5 g of p-diazodiphenylamine sulfate was dissolved in 45 g of concentrated sulfuric acid under water cooling. To this mixture, under stirring, add 1
．． 2g of paraformaldehyde was added slowly. At this time, the reaction temperature was made not to exceed 10°C. After that, 2
Stirring was continued for an hour under water cooling.

The reaction mixture was poured into 500 mfL of ethanol and the resulting precipitate was collected by filtration. 100% of this precipitate
ml of demineralized water, 20 g of a 40% by weight aqueous zinc chloride solution was added thereto, and the resulting precipitate was collected by filtration. This precipitate was dissolved in 100mM demineralized water, 30g of 50% by weight ammonium hexafluorophosphate aqueous solution was added,
The resulting precipitate was collected by filtration, washed several times with water, and dried under vacuum at 25° C. overnight to obtain diazo resin-1.

This diazo resin-1 was subjected to a coupling reaction with β-naphthol under alkaline conditions, and molecules of the resulting product were analyzed by gel permeation chromatography (hereinafter referred to as GPC).
The weight average molecular weight was 2050 in terms of standard polystyrene.

(Synthesis of lipophilic polymer compound-1) N-(4-hydroxyphenyl) methacrylamide 14
．． 2 g of acrylonitrile, 12.7 K, 58.0 g of ethyl acrylate, 8.6 g of methacrylic acid, and 3.2 g of azobisisobutyronitrile were dissolved in a mixed solvent of 90 ml of acetone and 90 mfL of ethanol, and the mixture was heated under a nitrogen stream at a high speed. The polymerization reaction was carried out at the same temperature for 20 hours. Hydroquinone 0
．． After terminating the polymerization reaction by adding 03 g of methyl cellosolve, 100 ml of methyl cellosolve was added, and acetone, methanol, and unreacted additives were removed by vacuum distillation. A methyl cellosolve solution of molecular compound-1 was obtained.

When the molecular weight of this lipophilic polymer compound-1 was measured by GPC, the weight average molecular weight was 60,000.

(Synthesis of Polymer Coloring Material-1) 50 g of 2-hydroxyethyl methacrylate, 10 g of acrylonitrile, and 70 g of dioxane were heated to 60° C. with stirring under a nitrogen stream.

100 g of a 40% by weight aqueous solution of sodium p-styrenesulfonate and 20 g of a 1% by weight aqueous solution of ammonium persulfate.
was added dropwise over about 1 hour, and the polymerization reaction was allowed to continue for another 6 hours with stirring at 60°C. See, I, Basic Blue 3 (
C,1,Ba5ic Blue 3) 5g, 50% water
g, 30 g of polymer solution dissolved in an aqueous solution of 5 g of acetic acid
In addition, the mixture was stirred at 100°C for 1 hour. After cooling, the reaction mixture was dropped into 100 ml of ether to precipitate, yielding 110 g of a polymer coloring material.

(Example 1 and Comparative Example 1) The following photosensitive solution -1 was applied to an aluminum plate-1 that had been electrolytically polished in a 1% aqueous hydrochloric acid solution, anodized in a 40% aqueous sulfuric acid solution, and further treated with a 1% aqueous sodium silicate solution. and -2 were coated to obtain photosensitive planographic printing plates -1 and -2, respectively. The amount of coating film was 2.0 g/m2 in both cases.

(Photosensitive liquid-1) ・Diazo resin-10.1g ・20% by weight methyl cellosolve solution of lipophilic polymer compound-1 5.0g ・Polymer colorant-10
, 2g ・Methyl cellosolve 17m (photosensitive liquid-2) ・Diazo resin - 10.1g ・20% by weight methyl cellosolve solution of lipophilic polymer compound-1 5.0g ・C, I, Basic Blue 3 0.08g - Methyl cellosolve 15 mfL photosensitive lithographic printing plates -1 and -2 were both heated at 400 mJ/cm.
The plates were imagewise exposed with 2 and developed with the following developer 1 to obtain negative image lithographic printing plates 1 and 2.

(Developer solution-1) ・Benzyl alcohol Log・Triethanolamine 3g・Sodium sulfite Ig・Sodium butylnaphthalene sulfonate g・Water 1000g Lithographic printing plate-1
Attach and -2 to the printing machine, and apply ultraviolet curing ink FD-
Printing was performed using OL-Beni (manufactured by Toyo Ink ■), and the plate surface was cleaned by wiping with Polymatic Plate Cleaner (manufactured by Eastman Kodak) every 500 sheets. In planographic printing plate-2, most of the color faded in the image area after washing for the second time (ioooth page), while in planographic printing plate-1, the color faded even after the 10th wash (soooth page). However, some color remained to the extent that the image area was clearly visible.

(Example 2 and Comparative Example 2) The following photosensitive solutions -3 and -4 were applied to the aluminum plate -1 to obtain photosensitive planographic printing plates -3 and -4, respectively. The amount of coating film was 2.0 g/m2 in both cases.

(Photosensitive liquid-3) ・Diazo resin-10.1g ・20% by weight methyl cellosolve solution of lipophilic polymer compound-1 s, Og・Schrimer-ACI
OL (Hiki Junyaku■'!A) *Polyacrylic acid 40% aqueous solution 0.04g・Cosmocolor-W-10-Blue (manufactured by Toyo Sakutatsu ■) 0.1g・Victoria Pure Blue BOH (Odogaya, Chemistry■ 0.04g ・Methyl cellosolve 15m (photosensitive liquid-4) ・Diazo resin-10.1g ・20% by weight methyl cellosolve solution of lipophilic polymer compound-1 5.0g ・Julima-ACI
OL (manufactured by Hiki Junyakugyo) *40% polyacrylic acid aqueous solution
0.04g Victoria Pure Blue BOH (manufactured by Hodokugaya Chemical Co., Ltd.) 0.04g Methyl cellosolve L5m pattern photosensitive lithographic printing plates -3 and -4 were both imaged exposed at 400 mJ/cm2 and developed as described above. It was developed with Solution-1 to obtain negative image lithographic printing plates-3 and -4.

Attach these to a printing machine and print using UV curable ink, Best Cure G Ai NT (manufactured by Toka Shiki ■).
The plate was cleaned with Ultra Plate Cleaner (manufactured by ABC Chemical ■) every 00 sheets. Planographic printing plate-4 was washed for the fourth time (2000th sheet), and the image area was almost completely discolored, whereas planographic printing plate-3, although the color had faded, the image area remained sufficiently blue. Ta.

[Effects of the Invention] As explained above, it can be seen that by using the photosensitive mechanism If of the present invention, a photosensitive lithographic printing plate with improved color loss in printing with ultraviolet curable ink can be obtained.

Claims (1)

[Claims] (1) In a photosensitive composition containing a photosensitive diazo resin, a lipophilic polymer compound, and a coloring substance, the coloring substance is
A photosensitive composition characterized in that it is a polymeric coloring material in which a dye is combined with a polymeric compound through ionic bonding.